[PATCH] reduce MAX_NR_ZONES: make ZONE_DMA32 optional

Make ZONE_DMA32 optional

- Add #ifdefs around ZONE_DMA32 specific code and definitions.

- Add CONFIG_ZONE_DMA32 config option and use that for x86_64
  that alone needs this zone.

- Remove the use of CONFIG_DMA_IS_DMA32 and CONFIG_DMA_IS_NORMAL
  for ia64 and fix up the way per node ZVCs are calculated.

- Fall back to prior GFP_ZONEMASK of 0x03 if there is no
  DMA32 zone.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

mm/page_alloc.c

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 2410a3c..5b5cbb5 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -70,7 +70,9 @@
  */
 int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES-1] = {
 	 256,
+#ifdef CONFIG_ZONE_DMA32
 	 256,
+#endif
 	 32
 };
 
@@ -85,7 +87,9 @@
 
 static char *zone_names[MAX_NR_ZONES] = {
 	 "DMA",
+#ifdef CONFIG_ZONE_DMA32
 	 "DMA32",
+#endif
 	 "Normal",
 	 "HighMem"
 };
@@ -1373,8 +1377,10 @@
 	int res = ZONE_NORMAL;
 	if (zone_bits & (__force int)__GFP_HIGHMEM)
 		res = ZONE_HIGHMEM;
+#ifdef CONFIG_ZONE_DMA32
 	if (zone_bits & (__force int)__GFP_DMA32)
 		res = ZONE_DMA32;
+#endif
 	if (zone_bits & (__force int)__GFP_DMA)
 		res = ZONE_DMA;
 	return res;